WILMINGTON, Del. (AP) — President Donald Trump's refusal to cooperate with his successor is forcing President-elect Joe Biden to seek unusual workarounds to prepare for the exploding public health threat and evolving national security challenges he will inherit in just nine weeks.

Blocked from the official intelligence briefing traditionally afforded to incoming presidents, Biden gathered virtually on Tuesday with a collection of intelligence, defense and diplomatic experts. None of the experts is currently affiliated with the U.S. government, raising questions about whether Biden is being pro...